Templates

Syntax#

t, err := template.Parse({{.MyName .MyAge}})
t.Execute(os.Stdout,struct{MyValue,MyAge string}{“John Doe”,“40.1”})

Remarks#

Golang provides packages like:

text/template
html/template

to implement data-driven templates for generating textual and HTML outputs.

Output values of struct variable to Standard Output using a text template

package main

import (
    "log"
    "text/template"
    "os"
)

type Person struct{
    MyName string
    MyAge int
}

var myTempContents string= `
This person's name is : {{.MyName}}
And he is {{.MyAge}} years old.
`

func main() {
    t,err := template.New("myTemp").Parse(myTempContents)
    if err != nil{
        log.Fatal(err)
    }
    myPersonSlice := []Person{ {"John Doe",41},{"Peter Parker",17} }
    for _,myPerson := range myPersonSlice{
        t.Execute(os.Stdout,myPerson)
    }
}

Playground

Defining functions for calling from template

package main

import (
    "fmt"
    "net/http"
    "os"
    "text/template"
)

var requestTemplate string = `
{{range $i, $url := .URLs}}
{{ $url }} {{(status_code $url)}}
{{ end }}`

type Requests struct {
    URLs []string
}

func main() {
    var fns = template.FuncMap{
        "status_code": func(x string) int {
            resp, err := http.Head(x)
            if err != nil {
                return -1
            }
            return resp.StatusCode
        },
    }

    req := new(Requests)
    req.URLs = []string{"https://godoc.org", "https://stackoverflow.com", "https://linux.org"}

    tmpl := template.Must(template.New("getBatch").Funcs(fns).Parse(requestTemplate))
    err := tmpl.Execute(os.Stdout, req)
    if err != nil {
        fmt.Println(err)
    }
}

Here we use our defined function status_code to get status code of web page right from template.

Output:

https://godoc.org 200

https://stackoverflow.com 200

https://linux.org 200